The invention generally relates to a device for controlling the closing of a power circuit breaker according to operational parameters. Preferably, it relates to a power circuit breaker including switching contacts, an energy store for transferring the switching contacts from an opening position into a closing position, a latching device for maintaining a tensioned state of the energy store and at least one closing actuator for releasing the latching device and enabling the energy store. Arranged in the path of the force transfer from the closing actuator to the latching device, may be a coupling element, which can be moved into an active position and an inactive position. Each of the parameters may cause the coupling element to be transferred into the inactive position, in which the force transfer from the closing actuator to the latching device is interrupted. An indicating element, which is dependent on the coupling element and can be moved into two positions corresponding to the states, may be provided for visually presenting the states of xe2x80x9cready for closingxe2x80x9d and xe2x80x9cnot ready for closingxe2x80x9d
A device for controlling a power circuit breaker is disclosed by DE 43 33 828 C1. It makes it possible for a user of the power circuit breaker to verify that the power circuit breaker can be closed by viewing the separate indicating element.
At the same time, the device prevents the energy store from being enabled in spite of activation of a closing actuator, such as a manually operated pushbutton or electromagnet, if one of the conditions is not satisfied. Since all the features or parameters which oppose closing of the power circuit breaker can be considered, the device makes an important contribution to the safety of the users of power circuit breakers and to the protection of electrical switchgear.
An embodiment of the invention is based on an object of providing a device which has a simplified construction and smaller dimensions. As a result, such a device may make it possible to use the advantages of the indication of closing readiness for all power circuit breakers which have a stored-energy mechanism.
The stated object is achieved according to an embodiment of the invention by at least one of the following further features:
the indicating element for closing readiness has working surfaces which can be acted on by the operational parameters and is able to be transferred by each of the parameters, counter to the action of a restoring force, from the xe2x80x9cready for closingxe2x80x9d position into the; xe2x80x9cnot ready for closingxe2x80x9d position,
the indicating element and the coupling element have interacting working surfaces for transferring the coupling element into its inactive position when the indicating element assumes the xe2x80x9cnot ready for closingxe2x80x9d position.
Consequently, the indicating element for closing readiness additionally has the logical OR function for the operational parameters. This has an advantageous effect on the space requirement of the device.
Within the scope of an embodiment of the invention, the indicating element for closing readiness can be moved about a pivot axis, the coupling element, which is designed in the manner of a lever, can be displaced in its longitudinal direction by the closing actuator and has a frame-like middle part, reaching over a fixed guiding surface with a clearance and being able to be transferred by two drivers of the indicating element into the active position or the inactive position. This likewise has the effect of saving unit volume.
In connection with the design explained above of the indicating element for closing readiness, the fixed guiding surface may be formed by an attachment which is arranged concentrically in relation to the pivot axis of the indicating element and against which one frame leg of the middle part of the coupling element bears in its active position, and if the drivers of the indicating element for closing readiness reach over the other frame leg of the middle part. This has the effect that the coupling element is taken up and guided in such a way that, on the one hand, it can be displaced in its longitudinal direction by a closing actuator and, on the other hand, it can be pivoted under the influence of the: indicating element to assume the active or inactive position.
In the case of power circuit breakers, it is also possible in connection with an embodiment of the invention for an indicating element representing the state of the energy store and a further indicating element, representing the position of the switching contacts, to be provided in addition to the indicating element for closing readiness. Within the scope of an embodiment of the invention, it can be provided that said additional indicating elements are likewise arranged such that they can be moved about the pivot axis of the indicating element for closing readiness and that the additional indicating elements each have a driver for driving the indicating element for closing readiness. This achieves, in a particularly simple and therefore space-saving way, the effect that two of the conditions for closing readiness of the power circuit breaker, that is xe2x80x9cswitching contacts openxe2x80x9d and xe2x80x9cenergy store tensionedxe2x80x9d, become effective directly, without relying on mechanical devices.
It can contribute to a compact type of construction of the device and at the same time to a reliable function that the closing latching lever bears a lug for direct forcible actuation of the indicating element for the state of the energy store in both positions (xe2x80x9ctensionedxe2x80x9d and xe2x80x9cemptyxe2x80x9d) and for actuating the indicating element for closing readiness only in the xe2x80x9cnot ready for closingxe2x80x9d direction.
In this case it proves to be expedient to arrange the indicating element for closing readiness centrally between the indicating elements for the switching position and for the state of the energy store, thereby creating a mechanically compact arrangement which allows the user an overview and makes it possible to see the state of the power circuit breaker at a glance.
Depending on the conditions at the place where a power circuit breaker is installed, there may be a different number of mechanical parameters to be supplied to the device according to an embodiment of the invention, as explained in the aforementioned DE 43 33 828 C1. In this case, it may prove to be advantageous to provide for the supplying of parameters based on the state of actuating magnets an intermediate shaft which has a first lever arm, interacting with the indicating element for closing readiness, and a second lever arm, interacting with a latching device controlling the opening of the power circuit breaker. This intermediate shaft allows, on the one hand, a separation of the parameters existing in the power circuit breaker itself from those which originate outside the power circuit breaker, for example xe2x80x9cdoor of the switchgear cell openxe2x80x9d or xe2x80x9cpower circuit breaker drawn outxe2x80x9d. In addition, the intermediate shaft makes possible a desired mechanical transmission ratio for adapting the stroke and force of actuating magnets to the device according to an embodiment of the invention and a desired spatial position in relation to the indicating element for closing readiness and the coupling element.
The intermediate shaft also offers the possibility of assigning an opening actuator to the device. This can take place by the intermediate shaft bearing as a third lever arm an opening lever arm, which can be acted on by an opening actuator. This can take place directly or with an auxiliary lever interposed, if the spatial position of the element to be coupled makes this appear to be necessary.